A large number of products are currently packaged in glass bottles, including such products include pickles, mayonnaise, and beverages, such as beer. Glass containers are usually made in modern glass container factories that typically comprise three primary operation areas. These three operation areas include the batch house, the hot end and the cold end.
The batch house is the area of the operation that handles the raw materials, such as the sand, sodium oxide, calcium oxide and the like, from which the glass is made. The hot end handles the manufacturing of the glass container from the raw materials, and includes equipment such as furnaces, annealing ovens, and forming machines. The cold end area of the operation handles the product inspection and packaging equipment, and may also contain the filling stations wherein the filler material (e.g. beer) is placed within the glass container.
The hot end of a glass works is the area of the plant where the molten glass is formed into glass products. The first machine in the hot end of the glass works is usually a furnace and its feeder, wherein a batch of raw materials is fed into a furnace at a slow controlled rate. Often, these furnaces operate at temperatures of up to about 1575° C. and produce a stream of molten glass. This stream of molten glass that emerges from the furnace is then made into a glass container.
There are currently two primary methods of making a glass container from this stream of molten glass, including the “blow and blow” method and the “press and blow” method. In both cases, a cylindrical stream of molten glass at its plastic temperature (typically somewhere between 1050° C. and 1200° C.) is cut with a shearing blade to form a cylinder of glass. This cylinder of glass is called a “gob”. The gob is then caused to fall by gravity and is guided by troughs and chutes into a blank “female” mold.
In the press and blow process with which the quick change plunger of the present invention is best employed, the solid gob of glass is converted into a parison having a hollow interior. A parison is a pre-container, and is generally somewhat cylindrically shaped, and does not yet include an exterior surface that mirrors the interior contours of the female mold that will give the bottle it its final shape.
The parison is formed in the press and blow process by the use of a metal plunger. The metal plunger is inserted into the gob to form a hollow interior cavity while pushing the glass out, and into the blank female mold. After the plunger is inserted into the interior of the gob (through what in the final bottle will be the open end of the bottle), the mold is flipped over. The glass is then blown out into the mold, through the introduction of compressed air into the interior cavity in the parison that is formed by the metal plunger. After the glass is blown out into its final form, it can then be cooled.
In a typical glass container plant, different types of containers are often manufactured on the same production line. This requires that plungers be changed from time to time. Additionally, plungers are subject to wear out and breakage, thus requiring that they be replaced. Currently, replacing a plunger is a difficult and time consuming operation. The difficulty of replacement is exacerbated by the fact that the plunger and mold are usually very hot, thus leading to a risk of burns and discomfort to the person changing out the broken plunger. The time consuming nature of the process adversely economically impacts the container making operation since it requires that the mold with which the plunger is used go “off-line” during the plunger replacement process.
Normally, a plunger is threadedly coupled to an axially movable piston that is positioned directly under the female mold, into the which the gob is poured, and in which the parison is formed. An example of such a female mold is shown in FIG. 1, that includes three separate cavities, 20, 22, 24. The three cavities are split into first and second halves 20A and 20B; 22A and 22B; and 24A and 24B. The halves of the female mold can come apart so that a formed bottle can be removed from the interior of the mold.
This “apart” configuration is shown in FIG. 1. However, the halves can be placed adjacent to each other so that they are together so that, for example, half 20A is placed adjacent to half 20B to sealingly engage half 20B when a gob is placed within the female mold 20, to form a bottle. The plunger assembly 40 is positioned under the mold assembly 20. Because of this close proximity, it is often difficult for a worker to get in, and remove the plunger as the plunger is in such close proximity to the female mold.
As such, it is therefore one object of the present invention to provide a device and method that facilitates replacing the plunger in a glass container mold making machine.